I've seen a lot of postings out there saying to add 11n_disable=1 to their modprobe config. While this got me working it was not helping my wireless speeds. After digging and playing I got mine to work. Please note this isn't a proper fix. We are just pulling in the latest drivers from upstream's backports project and installing them over the current ones.
If you did the modprobe hack you will need to undo it. Remove 11n_disable=1 from /etc/modprobe.d/iwlwifi.conf.
sudo apt-get install linux-headers-$(uname -r) build-essential
tar -jxvf compat-drivers-2013-01-23-1-u.tar.bz2
sudo make install
At this point reboot. (Yes you dont have to but it's a good way to test your change.)
Hopefully when your system is back you will see this from iwconfig
If you wish to revert the changes just run
lo no wireless extensions.
virbr0 no wireless extensions.
wlan0 IEEE 802.11abgn ESSID:"mynetwork_5ghz"
Mode:Managed Frequency:5.24 GHz Access Point: 32:24:A8:E8:17:34
Bit Rate=450 Mb/s Tx-Power=15 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Link Quality=70/70 Signal level=-34 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:2596 Invalid misc:267 Missed beacon:0
eth0 no wireless extensions.
sudo make uninstall
Hope this helps. If I can get some time I'll see if I can get a ppa going for this.